* [editor] Add bindkey-all function to show all bound keys
Function which allows you to see all the bound keys for all of
the different keymaps. It does accept arguments and passes them
through to bindkey -m "$keymap" so you could set a shortcut to
all keymaps as well if you wished.
Makes it much easier to see and grep what keys are bound to each of
the different keymaps.
When no arguments are given it will print keymap headers to stderr,
if given arguments it will not print anything extra to the screen.
* [editor] Update README to include information about bindkey-all funct.
